Typical beverage can ends for beer and beverage containers have an opening panel and an attached leverage tab for pushing the opening panel into the container to open the end. The container is typically a drawn and ironed metal can, usually constructed from a thin plate of aluminum or steel. Beverage can ends for such containers are also typically constructed from a cutedge of thin plate of aluminum, formed into a blank end, and manufactured into a finished end by a process often referred to as end conversion. These ends are formed by the process of first forming a cutedge of thin metal, forming a blank end from the cutedge, and converting the blank into a beverage can end which may be seamed onto a container.
These types of container ends have been used for many years, with almost all such ends in use today being the “ecology” or “stay-on-tab” (“SOT”) ends in which the tab remains attached to the end after a tear panel, including large-opening ends (“LOE”), is opened. The tear panel being a portion of the can end defined by a score length. The tear panel may be opened, that is the score may be severed, and the tear panel displaced at an angular orientation relative to the remaining portion of the can end. The tear panel remains hingeably connected to the remaining portion of the can end by a hinge segment, leaving an opening through which the user draws the contents of the container. In an LOE, the opening is at least 0.5 square inches in area.
Opening of the tear panel is operated by the tab which is attached to the can end by a rivet. The tab is attached to the can end such that a nose of the tab extends over a proximal portion of the tear panel. A lift end of the tab is located opposite the tab nose and provides access for a user to lift the lift end, such as with the user's finger, to force the nose against the proximal portion of the tear panel.
When the tab nose is forced against the tear panel, the score initially ruptures at a vent region of the score. This initial rupture of the score is primarily caused by the lifting force on the tab resulting in lifting of a central region of the can end, immediately adjacent the rivet. As the tab is lifted further, the score rupture propagates along the length of the score, eventually stopping at the hinge segment.
Throughout the use of ecology can ends, manufacturers have sought to save the expense of the metal by downgauging the metal of the ends and tabs. However, because ends are used for containers with pressurized contents, the score of the opening panel must have sufficient score residual to withstand such pressure, which in turn requires that the tab have a thickness of metal to provide strength to open the panel. Further, with the popular use of LOEs, additional problems arise with regard to openability of the ends. Because of the enlarged size of the opening panel (or tear panel), more stress is placed on the tab during opening of the tear panel, constraining efforts to further downgauge the tab. Also, the score in certain regions of the large-open tear panel are more difficult to open by the tab leveraging against the tear panel. This is especially true for the region of the score which is in the 5:00 to 6:00 clock position (with the rivet and tab nose being the 12:00 position).
Further, abuse during shipping, retail stocking and vending, due to rough handling of the filled containers, often causes problems with openability of the end. As an example of a problematic condition caused by handling abuse is the poor openability of a buckled container end. Due to dropping or abusive handling of filled containers, excessive pressure loads on regions of the end may cause a buckle of the end material. Such abuse, typically caused by dropping an upright container that is filled with carbonated fluid, results in a buckled end panel that deforms to form a bulge of metal of the panel.
The possibility of such buckling is a prevalent concern due to down-gauging of the end material, pressurization of the container, pasteurizing filled containers, environmental conditions such as excessive heat, and rough handling of pallets or cases of filled containers. In a metal container end, the buckle appears as a deformation or bulge of the metal in a region of the end panel, a condition that adversely affects the user's ability to open the end. Due to the geometry of the container and the ecology end panel, buckling of the end frequently is noticeable as a bulge of the end with a buckle in the 5:00 to 7:00 range of the end (with the middle of the tear panel positioned at 6:00). This type of buckled container end very often results in opening failure and resulting problems of a user trying to open the end.
Such a buckled end usually cannot be opened properly by the user. Instead, when the user lifts the tab and applies pressure on the tear panel with the tab nose, the score fractures at the wrong locations at the wrong time, usually resulting in a dramatic loss in leverage of the tab for opening the panel. In this situation, the tab is actuated against the tear panel by lifting the finger pull end of the tab, but the tab nose passes beyond the proximal peripheral edge of the tear panel, a condition often called “tuck under” of the tab. (See FIG. 11).
The tab that tucks under is, therefore, fully lifted by the user, though the tear panel is still not fully opened. In this situation, the tear panel remains attaches by a segment of the score usually at about the 5:00 to 11:00 of the tear panel (defined with the tab nose being at about the 12:00 region of the tear panel). When this condition occurs, the user often tries to open the tear panel with something other than the tab, often by applying force by an object or the user's finger.
Further, with LOEs, such problems with buckled ends are potentially greater. Because of the enlarged size and the shape of the opening panel (or tear panel), the score in certain regions of the large-open tear panel are more difficult to open by the tab leveraging against the tear panel. This is especially true for the region of the score which is in the 5:00 to 6:00 clock position. Therefore, large-opening ends may be difficult to open even when there is no noticeable sign of damage or buckle. Because of the additional force that may be required to open the large-opening tear panel with a tab, there may be more likelihood for non-specific tear of the metal away from the score. Also, because of the difficulty in opening the large-opening end, there is an increase in potential opening failure that results in “tuck under” of the tab. This type of opening failure also may result from the user opening the container too rapidly.
Because of these conditions, and the problem of potential tuck under of the tab, there is a need for an improved end structure that prevents or inhibits the total removal of the tear panel in the situation of an opening failure.
The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not provided by prior beverage can ends of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.